Improvement in hydraulic car-brakes



'NrTnn STATES THOMAS MCBRIDE, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN HYDRAULIC CAR-BRAKES.

Speeiication forming part of Letters Patent No. 147,338, dated February10,1874; application filed October 13, 1873.

To all whom 'it may concern:

Be it known that I, THOMAS MGBRIDE, of Philadelphia, in the county ofPhiladelphia and State of Pennsylvania, have invented certain new anduseful Improvements in H ydraulic Car-Brakes, and I do hereby declarethe following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which itpertains to make and use it, reference being had to the accompanyingdrawings, which form part of this specication, in which the figure shownis a representation of a vertical longitudinal section of my invention.l

This invention has ,relation to hydraulic car-brakes; and consists inthe combination, withthe conveying-pipes leading from the water-tank ortender and locomotive-boiler, of a glycerine tank or reservoir, havingcommunication with the pipe leading' from the boiler by means of a tubeprovided with a suitable valve, all as and for the purpose hereinafterdescribed.

Referring to the accompanying drawing, A is a locomotive, of which B isthe boiler, and C a tender. D is the conveying-tube, passing from theboiler to and beneath the tender and cars, having suitable devices forcoupling and uncoupling, and so arranged that the contents of the tubewill be held in place whether the sections be united or apart. Erepresents one of the cylinders through which hydraulic pressure isexerted to operate the brakes, said cylinders being provided withpistons, as shown, so connected to the brakes that as the pistons areforced out the brakes are applied to the wheels. A spring, H, isemployed to retract the brake andV piston after the hydraulic pressureis Withdrawn. I represents a tube leading from the water-tank in thetender to the tube D, a three-way valve, K, being located at thejunction of said tubes, from which leads to the boiler belowT thewater-line a pipe, L.

The operation is as follows: The valve K is rst opened in such manner asto allow the water from the tender to enter and ll the tube D, passingthereto through the pipe I,

and kept in this position until it is desired to apply pressure. Thevalve K is then turned, cutting off communication with the tender, andopening it with the boiler, whereupon the boiler-pressure is at oncebrought to bear upon the water in the tube, forcing the pistons out andapplying the brakes to the wheels.

The object of my invention being to avoid the danger of the waterfreezing in the tube D in cold weather, I provide the followingarrangement of devices: A tank, M, containing glycerine or othernon-freezing liquid, is pro, vided and placed in communication with thetube D by' means of a pipe, m, having a checkvalve, m. To apply theglycerine to the operation of the brakes, the check-valve m is openedand the liquid allowed to tlow from the tank :into the tube D until thelatter is filled all the way from the three-way cock to thebrake-pistons. The three-way cock is now turned, opening communicationwith the boiler. Pressure' is obtained which at once closes check-valvem', preventing flow of glycerine from tank. The column of glycerine intube D is moved along in the direction of the cylinders under cars bypressure from boiler, so that'the end of said column adjacent to cock Kwill travel as far, say, as the tube m. The vacuum which will be formedbetween the latter and the three-way cock will be filled by the waterrushing through said cock. Vhen the pressure is relaxed, by turning cockK, the water in tube D from, say, the cock K to the pipe m will pass upthe pipe I, leading to tender, and the glycerine column will assume itsoriginal position. Thus there will be no glycerine returned to theboiler or tender, for the water and glycerine will not be mixed in thetube D. The glycerine simply moves to and fro, and the water that enterstube D from boiler is pushed into tender on the return motion of theglycerine column.

I herein disclaim the pipes I, L, and D, and

the three-way valve K, combined as shown,

the same having been described and claimed in an application led by meJuly 2, 1873, now pending.

I-Izwing fully described my invention, what I with said pipe L by meansof the pipe m and claim as new7 and desire to secure by Letters valvem', 'as shown and set forth. Patent, is- In testimony that I claim theforegoing I rIhe combination7 with the conveying-tube have hereunto setmy hand this 30th day of D and pipes I and L, the latter eommuni-September, 1873. eating with the boiler B in order to obtain Vitnesses:THOMAS MGBRIDE. hydrzniliepressnre,as setforth7of the giyoerine M. DANL.GONNGLLY, teni; or reservoir M having communication EUGENE I?. EADSON.

